
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1 user-scalable=0">
    <title></title>
    <style type="text/css">
        .gray_filter{filter:url(#gray_filter);-webkit-filter:url(#gray_filter);}
        .opacity_filter{opacity: 0.4;}
    </style>
</head>
<body>
    <svg style="display:none;" version="1.1" xmlns="http://www.w3.org/2000/svg">
        <filter id="gray_filter">
            <feColorMatrix type="matrix" values="0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0"></feColorMatrix>
        </filter>
    </svg>
    <div id="app"></div>
</body>
</html>